What is UPF clothing?
We had two experts shed some light on sun-protective styles.
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With spring on the way, it’s safe to say there are sunnier days—and lots of sunscreen—ahead. Slathering on sunscreen isn’t the only way to stay safe from the sun, however. You can also get sun protection in wearable form, via UPF or UV-protective clothing.
But what does UPF mean? And is UPF-rated clothing worth the investment? We’re here to shed some light on the truth about sun-protective clothing.
What is the difference between SPF and UPF?
UPF, or ultraviolet protection factor, refers to how much ultraviolet (UV) radiation a fabric blocks. SPF, or sun protective factor, is a similar measure for determining sunscreen’s effectiveness. “Think of UPF as wearable sunscreen,” says Dr. Farah Moustafa, MD, dermatologist and director of laser and cosmetics at Tufts Medical Center. UPF blocks both UVA radiation, which is associated with skin aging, and UVB radiation, which can cause skin burning. Meanwhile, only sunscreens labeled “broad spectrum” block both types.
When it comes to interpreting UPF labels, don’t be fooled by the numbers. A UPF 50 fabric will block out 98% of the UV rays, whereas a UPF 30 fabric will block out about 97%. Moustafa says she typically recommends a UPF 50, but a minimum of 30 is vital.
What clothing has a higher UPF?
While a white T-shirt has a UPF of about 7, according to the Skin Cancer Foundation, some garments—especially darker, thicker fabrics—inherently have a higher UPF. The following factors determine whether a fabric is effective in protecting against the sun’s harmful UV rays.
Color: Darker colored fabrics typically have a higher UPF. As anyone who’s ever sat on a black leather car seat in the summer knows, dark-colored fabric gets hotter faster. This happens because darker fabrics are “absorbing the UV,” says Moustafa. Because heat is absorbed, less UV radiation passes through to your skin.
Tightness of weave: The less openings in the textile, the more light it blocks. A very dense material that’s tightly woven will have a higher UPF than one that is airy or loosely woven, Moustafa explains.
Wetness: While most UPF clothing is designed to stay protective when wet, says Moustafa, regular garments block the sun more effectively when they’re dry. For instance, a white T-shirt's UPF goes down to about 3 when it gets wet. “Anytime you take ordinary clothing and you wet it, you have then decreased its ability to protect you from the sun,” she explains, adding that it’s especially important to keep in mind with bathing suits.
Looseness: Whereas tight fabric stretches, separating fibers and creating more openings, looser-fitting clothing is less strained, giving it a higher UPF.
Fiber type: Certain fibers are better than others at blocking UV, according to Dr. Haskell Beckham, the senior director of innovation at Columbia Sportswear, which has a line of UPF-rated apparel. “Polyester does a better job in terms of scattering the UV and preventing it from getting through than some other fibers,” he says, emphasizing that fiber type produces just a slight difference. “It really comes down to the fabric construction and the yarn construction.”
How is UPF clothing made?
UPF clothing is created with chemical additives, tighter fabric weave, or a combination of the two. “The fabric construction alone usually does the job for us, and we'll add that additive into the fiber if we need to,” says Beckham. The additives aren’t “topical” finishes, meaning “they don't simply sit on the surface, they actually go into the fiber themselves, which makes them very, very durable.”
Should you still wear sunscreen under UPF clothing?
UPF could reduce the need for as much sunscreen, which is helpful for those who have sensitivities to sunscreen or are concerned about its environmental impact. However, make sure you still cover any exposed skin with sunscreen to avoid sunburn. “I don't think they replace one another,” says Moustafa. “I think they can be used in different ways.”
How long does UPF clothing last?
Because the UV additives are “really just special dye molecules,” that go into the fiber, the UPF protection is designed to last “as long as the color of the garment will last,” as Beckham says, which is typically a minimum of 30 to 50 washes. However, regardless of whether your garment is specifically UPF-treated or not, you can still increase its longevity. Farrah recommends letting clothes air dry or gently washing them, as the fibers naturally break down with each machine wash cycle, especially for clothing that’s not specifically engineered to have a high UPF.
Is UPF clothing worth it?
Because some fabrics have a higher UPF on their own, you might be wondering whether there’s an advantage to buying clothing specifically branded as offering UPF protection. The answer largely comes down to comfort. “Of course [with a] a winter jacket, we don't put UPF ratings on that, but we could,” says Beckham. The reason? The garments he typically tests for UPF are designed for warmer climates, where you’d be hesitant to bundle up or dress in dark, thick fabrics from head to toe. When specifically designed for UPF, light-colored clothing provides more sun protection than your standard white T-shirt, while still keeping you cooler than most darker garments. “The more 'open' you make the fabric, the more comfortable it is to wear in hot environments, but then it also lets more UV through,” he says. “So the challenge is actually creating a fabric that's very thin and as open as possible, but still blocks UV.”
“UPF clothing is tested and regulated, therefore you know what you’re getting in terms of sun protection,” Moustafa adds, also pointing out that while sunscreen requires proper and repeated application, wearing a piece of clothing asks much less of the wearer. “I really think it can only be helpful,” she said, especially given that many people don’t remember to reapply sunscreen every two hours, and in particular for kids. “I think it takes a lot of that burden off if you have something that you're wearing like on your body and you don't have to [say] ‘oh, did I put enough on?’”
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